The current pair of fusion models for fusing the information of building interior and natural environment treats the two separately due to a large amount of computation, which leads to low efficiency and poor results of fusion. Regarding the above-discussed problems, the study constructs a fusion model of building interior and the natural environment under I.M. Pei’s design idea. Following an examination of how the interior of the building and the natural environment relate to one another by I.M. Pei’s design concept, information about the natural environment and the interior of the building is obtained through the use of remote sensing technology and 3D modeling technology. To finish the development of the model, the neural network model is used after the training of the parameters, and then, feature-level and information-level fusion of the obtained data is carried out. The validation data of the model showed that the fusion efficiency of the constructed model was improved by about 58.9%, and the fusion effect was significantly improved.